[The 487th case: prominent eyes, headache, blurred vision]

Area of Science:

• Rheumatology
• Oncology
• Pathology

Background:

• Erdheim Chester disease (ECD) is a rare non-Langerhans cell histiocytosis.
• It can manifest with diverse systemic symptoms, often leading to misdiagnosis.

Purpose of the Study:

• To highlight the diagnostic challenges and clinical presentation of Erdheim Chester disease.
• To emphasize the importance of considering ECD in patients with unexplained systemic inflammation and specific organ involvement.

Main Methods:

• Case report of a 51-year-old male patient presenting with ophthalmologic and retroperitoneal symptoms.
• Initial diagnosis of granulomatosis with polyangiitis, treated with prednisone and cyclophosphamide.
• Subsequent diagnosis of ECD confirmed by biopsy and pathological examination.

Main Results:

• The patient initially responded to immunosuppressive therapy for presumed granulomatosis with polyangiitis.
• New dural masses and osteosclerosis indicated a different underlying pathology.
• Diagnosis of Erdheim Chester disease was established.

Conclusions:

• Erdheim Chester disease requires a high index of suspicion due to its varied and sometimes overlapping clinical features.
• Prompt diagnosis and targeted therapy, including BRAF inhibitors like Vemurafenib, can lead to stable disease.
• Clinicians must be aware of ECD's manifestations for accurate differential diagnosis in complex rheumatologic and oncologic cases.